Many of the stars have contacted the FBI to investigate a ring of hackers and phishers who trade their purloined pictures to build a collection, and have hired high-powered lawyers to urge websites to take the photos down.

One source said: “This isn’t one rogue hacker, this is the work of a ring of hackers. It will take time to track them down. The early theory is that at least some of those in the hacking ring are US- based because some of the names on the ‘master list’ are actresses or personalities who are only known to someone who watches US cable TV.”

While there are many A-list women on the list, some of those who might be better known in the US — and whose photos have not yet emerged — include “So You Think You Can Dance” finalist Ellenore Scott; Clare Bowen, known for the ABC series “Nashville”; American model Emily DiDonato; “Deal or No Deal” beauty Tameka Jacobs; and Erin Cummings, who had minor roles in “Charmed” and “Star Trek: Enterprise.”

While the FBI didn’t return calls, Bruce Anderson, whose Cyber Investigation Services is working with one celeb who was targeted, said: “Electronic fingerprints can be left in a variety of ways. The FBI would look at victims’ accounts with Apple to see if anybody has logged in. Is there a series of IP addresses linked to the account? They’d look at the devices of the celebrity to see if someone had access to their computer or their phone, or had got past the security into the iCloud . . . It is a pretty cumbersome prospect, particularly with so many pictures out there. “